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Please Help Diagnose P0449 Code On 02 Silverado 5.3l

SandyNeck

By SandyNeck
in Ask A GM Technician

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SandyNeck Enthusiast

SandyNeck

Posted
Posted

Hey Guys,

I have an 02 Silverado 4x4 with a 5.3L engine. My SES light is on and I need help diagnosing the cause of a P0449 code. I understand that this code indicates a "Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction". It is sometimes accompanied by a P0440 code "Evaporative Emission Control System Malfunction". When I clear the code, the P0449 soon reappears, usually at the second startup. I tried replacing the Purge Canister Solenoid, but the code still returns. The pink wire to the purge solenoid does have power to it when the key is in the 'on' position. I understand that the PCM activates the solenoid by closing the ground terminal on its connector. I tried applying power and ground directly to the solenoid, and I can hear it clicking. All this is leading me to believe that the problem is in the application of ground further upstream from the solenoid. The ground wire enters a flexible conduit very close to the solenoid connector, making it very difficult to trace. I suspect there's a relay somewhere in the circuit that applies ground to the solenoid when the PCM tells it to, but I have no idea where it is located. Can anyone give me some direction on this as far as possible causes, other things I should check, wire routing, component location, etc? I just don't know where to look from here. For what it's worth, the truck seems to be running fine otherwise and I've already replaced the gas cap with a new GM part. Any help or direction is grately appreciated!

bill190 Enthusiast

bill190

Posted
Posted

It's pretty much impossible to work on electrical problems such as this without a GM factory wiring diagram manual. This is because it is impossible to trace wires without tearing the vehicle apart! Anyway you can order an Electrical Diagrams manual from a GM dealer (for your specific year/model vehicle). You might want to get the full service manual set of 4 books.

intruderrider New Member

intruderrider

Posted
Posted

I,m having the same problem with my 06 4x4 5.3 liter with 61,000 miles. If you find a solution can you post it? I would assume from the sounds of your problem that whatever fixes your problem, may also be the fix for my problem. I'll do the same in return, i plan on working on my truck over the weekend.

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